The invention relates to an over-center self-closing hinge for cabinet doors, having: a four-joint articulation with two links, a single-arm lever journaled at its stationary end in the wall-related part of the hinge and formed by a compression spring whose free end can swing in a plane at right angles to the hinge pivot axis, and a cam body which is disposed in the area of the wall-related journal of the inner link (the one closer to the wall). The cam body is journaled on an axis in the wall-related part of the hinge, and additionally is supported at opposite ends of the inner link in the area between the two journals, and has a cam face engaged by the spring under bias.
IA self-closing over-center hinge of this kind is known (DE-OS No. 24 08 057), in which the lever rotating at right angles to the axis of articulation and resiliently biased against the cam face of the cam body is formed by a leaf spring biased at one end directly against the cam face. This hinge has proven practical and is used in great numbers where the door closing or holding force to be applied by the over-center mechanism is not too high. On account of the special geometry of four-joint hinges, the angular deflection of the inner link from the open position to the closed position, or vice-versa, is decidedly less than the angular deflection of the door hung on a cabinet with the hinge. It follows that the effective angular length of the face of the cam body that is affixed to the wall-end pivot eye of the inner hinge link is relatively short. In order to transmit a high force to the inner hinge link, and thus to the door-related hinge part, and ultimately to the door, with such a short rotation of the cam body, a spring must be used which is under high bias, since the short effective length of the cam does not permit any great spring movement. This bias, however, then acts constantly not just between the lever and the cam body, but also on the pivot of the inner link. Consequently, with a view to the useful life of the hinge, the door-holding force that can be achieved in the known hinges is limited.
Accordingly, the problem to which the invention is addressed is to improve the known hinge such that its over-center mechanism will apply a greater closed-door holding force without reducing its useful life.